This is the 7124th most frequent Russian word.
боснии
"Боснии" is the genitive or prepositional case of "Босния," meaning "Bosnia" in English, referring to the country.
In this sentence, "Боснии" is in the genitive case, indicating possession or association with Bosnia, which is the geographical location of the mountains.
Я мечтаю посетить горы в Боснии.
I dream of visiting the mountains in Bosnia.
Here, "Боснии" is again in the genitive case, referring to the country Bosnia, indicating a relationship to the culture mentioned.
Культура людей в Боснии очень разнообразна.
The culture of people in Bosnia is very diverse.
In this example, "Боснии" denotes the genitive singular of Bosnia, expressing the attractions belonging to or located in Bosnia.